Come rain or shine 750,000 fans are expected to turn out on Sunday for cycling's most revered one-day race, the Tour of Flanders, for a Tadej Pogacar and Mathieu van der Poel showdown.

The all-rounder Pogacar won the Tour de France, Giro d'Italia and world championships in 2024, while Van der Poel, who is 10 kilos heavier than the Slovenian, is the most powerful one-day racer, and has multiple mountain bike and cyclocross titles.

Pogacar has also confirmed he will ride the Paris-Roubaix with its 54km of cobbles and no hills in next Sunday's big one.

Van der Poel won both last season.

Each has seven wins in the Monuments and last time the two went head-to-head Van der Poel came out on top at Milan - San Remo in March.

"Mathieu is one of the best sprinters in the peloton," said the effervescent Pogacar. "Flanders is a very different race. But if there's a sprint, I'll do my best."

While Pogacar won here in 2023, Van der Poel is one of seven men to have won it three times and could become the first to win a fourth.

In this epic 270km struggle through lush Flemish plains, Van der Poel's weight might be an advantage for the distance and the 18 cobbled sections.

For the slighter Pogacar, there are 17 short, punchy hills where he can exercise his devastating kick.

Belgian hopes would normally rest on Wout van Aert. He has struggled to find any form since a win at the Vuelta last year but Pogacar is not ruling him out.

"Wout seems pretty good to me. He's on the pace," Pogacar said. "He'll be in there on Sunday."

Denmark's Mads Pedersen and Filippo Ganna of Ineos are two other on-form riders to watch out for.

First staged in 1913 the Tour of Flanders was designed to reflect the stoicism of the Flemish. The winner is often a tough, tactically-minded rider ready to give every last drop for victory.

Van der Poel won the 2020, 2022 and 2024 Flanders and has twice been runner-up, but after winning the Milan - San Remo in March he picked out Pogacar as favourite for this one.

"There are many more hills here for him to attack on. It'll be hard, but then it always is," said the 30-year-old Dutch phenomenon.

After the 114km mark, there is a cobbled hill every 8km or so, constantly whittling down the field which will start with 25 teams of seven.

Each hillside in the latter part of the race is turned into a giant makeshift party pub, with beer tents and food caravans before an after-party that goes on late into the night.

Pogacar said of his 2023 win he could retire happy after soloing home thanks to a series of devastating attacks.

He opted not to defend his title in 2024 to target an elusive Giro-Tour double last achieved by the late Marco Pantini in 1998.

There are five ultra-long one-day bike races known as the Monuments, and the Tour of Flanders is considered the greatest because of the constant steep, narrow climbs coupled with crowds that even a 100 years ago began to tip over half a million.

The other four Monuments are Milan-San Remo, which calls for patience, the mudfest of Paris-Roubaix with its perilous rough-hewn cobbles, Liege-Bastogne-Liege through the winding forested lanes of the Ardennes, and the Tour of Lombardy which is a climbers' classic.

Shuttle buses and extra trains have been laid on throughout Flanders for what is regarded by many as an unofficial world championship. (AFP)